Top wired electrical cap and connector



Dec. 3, 1957 B. c. WEBSTER TOP WIRED ELECTRICAL 0 A? AND CONNECTOR 2 Shqets-Sheet 1 Filed Sept. 2, 1954 Dec. 3, 1957 B. ,c. WEBSTER TOP WIRED ELECTRICAL CAP AND CONNECTOR Filed Sept. 2, 1954 {329.11.

.2 Sheets-Sheet 2 lNVE 179 ATTORNEYS 2,815,495 Patented Dec. 3, 1957 2,815,495 TOP WIRED ELECTRICAL CAP AND CONNECTOR Application September 2, 1954, Serial No. 453,880 10 Claims. (Cl. 339-174) This invention relates to electrical devices, particularly to a top wired electrical cap and connector, and has for an object to provide an improved construction for this type of device, including improved means for connecting the lead wires to the contacts in the electrical device, either the cap or the connector, which does not require the use of binding screws with their objections of requiring considerable time for making the connections of the conductor wires to the contacts and their liability of loosening up in use, resulting in a loose connection for the wire, with consequent loss of proper electrical connection and danger of short circuits.

Another object is to provide a device of this character in which the body comprises a pair of insulating body members which are connected together for relative movement by any suitable means, such, for example, as screws, and in which by operating these screws to draw the body members together, this action will clamp the bated ends of the conductor wires against the stationary contacts in the device or some element connected therewith, to effeet the electrical connection between the conductor wires and the contacts, and also to secure these wires to the device.

Another object is to vice of provide a construction in a dethis character involving a plurality of stationary the respective contacts may all be effected simultaneously and in one operation.

With the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawings forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details otf construction and arrangement shown, but may embody various changes and modifications Within the scope of the invention.

In these drawings:

Fig. l is a side elevation of an attachment plug cap comprising this invention;

Fig. 2 is a top plan view thereof;

Fig. 3 is a bottom view;

Fig. 4 is a vertical section substantially on the line 44 of Fig. 2, showing the conductor wires in place;

Fig. 5 is a vertical section substantially on the line 55 of Fig. 2;

Fig. 6 is a vertical the body separated;

Fig. 7 is a top plan view of the lower member of Fig. 6 but showing one of the contacts removed;

Fig. 8 is a bottom view of the upper member of Fig. 6 removed from the shell;

Fig. 9 is a perspective view of one of the contacts;

Fig. 10 is a detail view looking at the upper end of one of the contacts from the left of Fig. 9;

Fig. 1 1 is a side elevation of a connector comprising the invention, and which may be used with the cap of Figs. 1 to 9;

vFig. 12 is a bottom view of this connector;

section showing the members of with their Wider portions Fig. 13 is a vertical section substantially on line 1313 of Fig. 12, but showing the conductor wires in place;

Fig. 14 is a section substantially on line 1414 of Fig. 12;

Fig. 15 is a vertical section separated;

Fig. 16 is a top plan view of the lower member of Fig. 15, with one of the contacts removed;

Fig. 17 is a bottom view of the upper member of Fig. 15 removed from the shell, and

Fig. 18 is a perspective view of one of the contacts.

Referring first to the cap form of the device shown in Figs. 1 to 10, the device comprises two body members 1 and 2 of suitable molded insulating material enclosed in a protective metal shell or casing 3, and to more readily identify these two elements the member 1 will be called the upper member and the member 2 the lower member of the insulated body. The upper member is a tight or forced fit in the shell 3 so that it is permanently held in position therein when assembled, and to assist in holding the body member tight in the shell it may be provided with a series of small, rounded projections 4, as shown in Fig. 8, which are preferably in the form of longitudinal ribs on the surface of this member of from five to ten thousandths of an inch in height, and of any suitable length, say, for example, about three eighths of an inch. The lower member 2, although closely fitting the shell 3, has longitudinal sliding movement in this shell so that it may be removed for mounting the stationary contacts of the cap in it, and also shifted for effecting the connections between the conductor Wires and these contacts.

The contacts for this cap may be the standard straight, flat contact blades projecting from the lower side of the member 2, but in the form shown comprise the locking type of blade contacts. This arrangement comprises three blade contacts 5 for connection to the conductors of a three-wire system and a fourth blade contact 6 acting as a grounding contact for connection to the grounded wire in the insulated cable 7. These blades comprise a narrower intermediate portion 8 and a transversely curved wider free end portion 9 providing a locking shoulder 10 facing inwardly and located between the free end of the blade and the end of body member 2, these blades being adapted to be inserted in a receptacle or connector and then turned a very short distance about the axis of the cap to move these shoulders 10 behind locking shoulders in the connector or receptacle, as will be more fully de scribed in connection with the connector shown in Figs. 11 to 18. The upper end portions of the contact blades are longitudinally slit as indicated at 11 (Figs. 9 and 10), forming an upright lug 12, and the remaining portion is curved and oifset laterally, as indicated at 13, terminating in a lateral lug or tongue 14, in the form shown arranged at substantially right angles to the body portion 3. This tongue comprises an upper or top member for the contact in the general form of a horizontal plate. Between the narrow portion 8 and the lug 14 is an intermediate transversely curved Wider portion 15.

These contacts are mounted in the lower body mem ber 2, and for this purpose this member is provided with curved slots or openings 16 in its lower wall for the contacts 5 and another slot 17 for the contact 6. The contact 6 is the same as the contact 5 except that its lower end has a short extension in the shape of a lug of less width than the blade folded back upon itself, as shown at 18 (Figs. 1, 3 and 5) to form a thickened portion at one side of the blade, and the slot 17 has a Wider portion or recess at one end, as shown at 19 (Figs. 3 and 7) to permit this thickened portion 18 of the blade to pass through the slot 17. Mounted in the member 2, the blades are seated in slots 16 and 17 15 located in these slots, and

showing the body members the laterally curved portions 13 seating in chambers or recesses formed in central boss 21 in the top wall of the member 2. The chambers or recesses 20 are extensions of the slots 16 and 17 and form continuations thereof. The laterally extending lugs or tongues 14 at their upper ends seat on upstanding ribs or projections 22 formed on the bottoms of the recesses 23 in the top wall of the member 2. The top surfaces of the ribs or projections 22 form shoulders on which the top plates or tongues 14 of the contacts are supported, and have in these upper surfaces shallow, radially extending channels or grooves 24 in which is seated a rib 25 (Fig. 10) on the under side of the tongue or top member 14 to prevent it from swinging laterally off the member 22. The lugs 12 are at the outer side of the boss 21 and against shoulders 16a forming extensions of an end of the slots 16 at one side of chamber 20, as shown in Fig. 7. In this position the lower portions of the blade contacts, including the intermediate portions 8 and the wider free end portions 9, project from the lower surface of the body member 2 where they may be inserted in the entrance slots of the connector or receptacle with which the device is used. These contacts are preferably a tight or forced fit in the slots 16 and 17 so as to be retained therein when the lower member 2 is removed from shell 3.

The upper member 1 of the insulated body, as previously indicated, is a tight fit in the shell 3, and in its lower surface, as shOWn in Fig. 8, is provided with raised lugs 28 forming three sides of three-sided recesses 27, one in alignment with and over each of the ribs 22 of the lower member, and thus also in alignment with the tongues 14 of the contacts mounted in the lower member. This member 1 also has an entrance passage 28 in its upper surface from the lower end of which lead individual passages 29 for the individual lead wires 30 in the insulated cable 7. In making the connection of these conductor wires to the stationary contacts, their bared or stripped free ends 31 from which the insulation has been removed are inserted through the passages 29 into positions on top of the laterally extending tongues 14 of the contacts and in the recesses 27 in the lower surface of the upper member 1, the outer walls of the bosses 26 operating as limit stops to limit the amount these conductor wires may be inserted, and the side walls 32 retaining the bared ends 31 of the wires in position and preventing them from sliding laterally off the tongues 14 of the contacts. The opening or passage 28 is of a size to receive the lower end of the insulation of the cable 7, while the upper portions of the individual passages 29 for the individual conductor wires are of a size to receive the end portions of the insulation on the individual wires, as indicated in Fig. 4.

The two body members 1 and 2 are connected by screws 33 passing throughopenings 34 in the upper member 1 and threaded at their lower ends in tapped inserts 3S molded in the lower member 2. In making the connections between the conductor wires and the contacts in the member 2 the screws 31 are lossened sufficiently to permit the member 2 to be shifted away from the member 1 a sufiicient distance to permit the bared or stripped ends 31 of the conductor wires to be in the notches or recesses 27 on top of the tongues 14 of the contacts, as above indicated and as shown in Fig. 4. Then by tightening up on the screws 33 the member 2 is drawn toward the member 1, firmly and securely clamping these free ends 31 of the conductor wires between the bottoms of the recesses 27 and the tongues 14 of the contacts, effecting a tight, firm grip and connection between the conductor wires and the contacts and also securing a very eifective electrical contact between them. It will be seen that this means of connecting the wires to the contacts eliminates the usual binding screws; that therefore it is not necessary to wind the wires around the screws, and the single operation of setting up the screws simultaneously connects all the conductor wires to their respective contacts.

By reducing the neck of the screws 33, as shown at 36, immediately under their heads 37 and locating this reduced portion in a slot 38 in the top wall 39 of the shell 3, the screws will be held against longitudinal movement relative to the shell, and therefore the operation of loosening these screws will cause the lower member 2 to be shifted downwardly away from the upper member 1 to provide sufficient space between them for insertion of the bared ends 31 of the conductor wires to their proper position on top of the tongues 14, and the action of this reduced portion and slot will also retain the lower member 2 in this position while the wires are being so inserted. After the wires are inserted, all that is necessary to complete the connection of the wires to the contacts is to tighten up the screws 33.

These screws and the top wall 39 of the casing may also be employed for mounting strain relief clamps for the insulating cord 7. These clamps are indicated at 40, each comprising an upright transversely curved cordgripping body portion 41 with outwardly extending cars 42 on the opposite sides thereof, and each provided at the lower end of the portion 41, and at substantially right angles thereto, with a lower foot portion 43 guided for lateral radial sliding movement in an upwardly offset portion 44 formed in the top wall 39 of the shell. This forms a guide channel between the shell and the top of the member 1 of the body for sliding movements of the foot 43 to permit movement of the clamp toward and from the cord 7. The foot 43 is provided with a longitudinal or radial slot 45 embracing the screw, and it will be seen from this arrangement that as the screws are tightened up in drawing the lower member 2 toward the upper member 1 and clamping the conductor wires against the stationary contacts, the top wall of the raised portions 44 on opposite sides of the slot 38 will be clamped against the foot 43 and will clamp the cord clamp in adjusted position. These clamps can also be clamped with a tight grip on opposite sides of insulated cord 7 by means of transverse screws 46 passing through the ears 42 of one of the clamps and threaded into the ears on the other clamp. To increase the grip of these clamps on the cord 7 the curved gripping portion 41 may be provided with a suitable gripping means, that shown comprising an opening 47 (Fig. 6) of any suitable shape, preferably substantially triangular shape, as indicated.

Referring now to the connector form of the device, shown in Figs. 11 to 18, the conductor wires from the insulated cord are connected to the receptacle contacts in the connector in the same manner as in the cap shown in Figs. 1 to 10, and certain parts of this connector are the same as those used in the cap. Thus the protective metal shell 3 is the same as that used in the cap of Figs. 1 to 10, although its side walls may be made somewhat longer if desired, to more fully enclose the somewhat longer body member 48 of the insulated body, as it is somewhat longer than the lower member 2 of the cap. This lengthening of the shell, however, is not necessary, and a portion of the member 48 may project from the lower end of the shell, as indicated.

The upper member 1 of the insulated body is the same as the member 1 of the cap, and has the same passage 28 in the top wall for entrance of the insulated cord 7 corresponding to the passage 28 of the first form, and has the individual passages 29 leading from the lower end of this passage 28 for passage of the individual condoctor wires 30 from the cord for connection of the bared ends 31 of these wires to the receptacle contacts indicated at 49, mounted in the lower member 48 of the body. As this member 48 is the receptacle portion of the connector, the contacts 49 are mounted in chambers or spaces 50 in the member 48 opening at their upper ends through the top of this member and with curved slots 5 1 and 5 2 leading to these chambers through the lower surface of the member 48 for entrance of the curved contact blades 5 and 6 of the cap, the slot 52 being provided with a wider notch 53 at one side and one end to permit passage of the enlarged lug 18 of the grounding contact 6 of the cap. The chambers 50 are really extensions of the slots 51 and form continuations thereof. The chambers are somewhat wider than the lengths of the slots, thus providing inwardly facing locking shoulders 63 at the inner side of the slots at one end thereof. The contacts 49, as indicated in Fig. 18, may each comprise an upper or top member 54 comprising a horizontal plate with a downwardly extending lug or ear 55 at one end, and the other end in the form of a rounded lug or tongue 54a. On the under side of this plate are mounted spring contact fingers 56 adapted to receive the contact blades 5 and 6 of the cap between them and by their spring action to grip the opposite sides of these blades and provide good electrical contact between them. The fingers 56 may have lateral feet 57 secured to the base or plate 54 at their upper ends, and at their lower ends may be curved laterally outwardly, as indicated at 58, to guide the contact blades 5 and 6 into position between the members 56.

In mounting these contacts in the member 48, the fingers 56 are inserted from the top of the member 48 into the chambers or spaces 50 with the rounded inner ends 54a of top plate 54 and feet 57 resting in recesses 59 in the central boss 60 of the top surface of the member 48 at the inner sides of chambers 50 and at their outer ends seating on upstanding lugs 61 on the opposite or outer sides of chambers 50 with the lug or car 55 extending down into the recesses 62 and on the outer sides of the lugs 61 to hold these contacts in position. The bottom surfaces of the recesses 59 and top surfaces of lugs 61 form shoulders supporting the top portions or plates 54 of the contacts.

The upper and lower members 1 and 48 of the body are connected the same as in the cap by means of screws 33 passing through openings 34 in the upper member 1 and threaded at their lower ends into tapped inserts 35 molded in the lower member 48, and the upper ends of the screws are reduced at 36 under their heads 37 to position them in the slots 38 in the top wall 39 of the shell, the same as in the cap.

In making the electrical connection between the conductor wires in the cord 7 and the contacts 49, the screws 33 are loosened, forcing the lower body member 48 downwardly away from the upper member 1 a sufiicient distance for insertion of the bared ends 31 of the conductor wires into the recesses 27 in the lower wall of the upper member 1 and to a position on top of the base plates 54 of the contacts 49, as indicated in Fig. 13. Then by tightening up on these screws 33, the lower member 48 is drawn upwardly against the under side of the upper member 1, firmly clamping the lead wires against the top walls 54 of the receptacle contacts 49 and between these contacts and the bottom walls of the recesses 27, as indicated in Fig. 13. This effects a tight clamping grip of the lead wires against the receptacle contacts, to not only secure the wires to the connector but also to secure a very effective electrical contact between the conductor wires and the receptacle contacts, and as described in connection with the cap, this connection between each conductor wire and its respective receptacle contact is effected simultaneously with that of each of the other wires and contacts by the simple operation of setting up' screws 33. Also the connections between all of the wires and the contacts are eifected simultaneously and with a single operation. As in the first form, no binding post screws are required, with the advantages secured in the first form of eliminating the operations of winding the wires around the screws and setting up the screws.

9 After the contact blades inthe slots 51 and 52 of 5 and 6 of the cap are inserted the connector and into engagement with the. contacts 49 to effect the electrical connection between them, a limited lateral turning movement between the cap and connector may be made to lock the cap and connector together against longitudinal separation, as, for example, by pull on the conductor cords 7 connected to the cap and connector. This may be done by turning the cap to the right or clockwise about its longitudinal axis shifting the contact blades 5 and 6 in the slots 51 and 52 (these slots being long enough to permit this) to carry the shoulders 10 on the contact blades behind locking shoulders or surfaces 63 at the ends of chambers 50 at the inner sides of the slots 51 and 52 and extending away from one end of each slot. This is done while the blade contacts 5 and 6 remain in engagement with connector contacts 49, maintaining the electrical connection between them which was established when the blade contacts were inserted in these slots. To unlock the cap and connector all that is necessary is to turn the cap in the opposite direction to shift the shoulders 10 from their positions behind the retaining surfaces 63 at the ends of the slots 51 and 52 in the chambers 50.

The same type of cord clamp or strain relief is used for connecting the insulated cord 7 to this connector as is secured in the form of cap shown in Figs. 1 to 10. The clamping members 40 of this cord clamp are secured to the connector by the same construction and the same means as shown in'Figs. l to 7, and they are secured to the body and the shell 3 in the same manner as shown in these figures and are clamped about the cord in the same manner as in Figs. 1 to 6.

It will be seen from the above that this construction and arrangement-is a very simple one, and forms a very effective and easily and quickly operated means for connecting the conductor wires to the stationary contacts of an electrical device, either the plug-in cap or the connector, and eliminates the usual binding post screws with their objections, the connections from the conductor wires to the. stationary contacts can be easily and quickly effected in a single operation, and when these connections are made the conductor wires are firmly and securely clampedwith no danger of their becoming loose in use, and a very effective electrical connection is provided between the conductor wires and the stationary contacts.

Having thus set forth the nature of my invention, I claim:

1. In an electrical device of the character described, a body of insulating material consisting of upper and lower members only, stationary contacts mounted in the lower member each having an upper end in the form of a horizontal plate and a downwardly extending portion below said plate, shoulders on the upper side of the lower member on which said plates are supported, the upper member having downwardly facing radially extending recesses on its lower side immediately over said plates, said recesses being closed on their opposite sides and outer ends and open at their inner ends, said upper member provided with passage means extending longitudinally through it from its top wall whereby the bared ends of conductor wires may be inserted through the open sides of said recesses with the outer ends of the recesses forming limit stops for the ends of said wires to position them in the recesses over the plates, and screws connecting the body members and operative to draw them together to clamp the wires to the contact plates.

2. In an elecrical device of the character described, a body of insulating material comprising upper and lower members, stationary contacts mounted in the lower member each having a laterally extending upper end portion and a downwardly extending portion below it, shoulders on the upper side of the lower member on which said upper end portions are supported, the upper member having clamping surfaces on its under side over said end portions and passage means whereby the bared ends of conductor wiresmay be inserted between said clamping surfaces and the tops of said end portions, screws conmeeting the body members mounted in one of said members and having threaded connection with the other member, said screws operable when turned in one direction to shift the lower member toward the upper member to clamp said conductor wires against said end portions of the contacts, and means holding the screws against longitudinal movement in the first member so that their operation in the opposite direction will shift the lower member away from the upper member to permit insertion of the conductor wires between them.

3. In an electrical device of the character described, a body of insulating material comprising upper and lower members, a metal protective shell enclosing both of said members and including an upper end wall extending over the top of the upper member, stationary contacts mounted in the lower member having upper end portions supported by said member, the upper member having clamping surfaces on its under side over said end portions and passage means whereby the bared ends of conductor wires may be inserted between said surfaces and said portions, the said lower member being movable in and guided by the shell toward and from the upper member, screws passing through said upper member and the top wall of the shell and having threaded connection with the lower member, and cooperating means on said top wall of the shell and screws holding the screws against longitudinal movement in the shell and upper member whereby operation of the screws in one direction will draw the lower member toward the upper member to clamp the wires against the contacts and operation of the screws in the opposite direction will shift the lower member away from the upper member to permit insertion of the wires.

4. In an electrical device of the character described, a body of insulating material comprising upper and lower members, a metal protective shell enclosing both of said members and including an upper end wall extending over the top of the upper member, said lower member being movable in the shell toward and from the upper member, stationary contacts mounted in the lower member having upper laterally extending end portions supported by said member, the said upper member provided with clamping surfaces on its under side over said end portions and passage means to permit insertion of the bared ends of conductor wires to positions on said upper end portions of the contacts under said clamping surfaces, screws passing through the upper member and having threaded connection with the lower member whereby operation of the screws in one direction will draw the lower member toward the upper member and clamp the lead wires against the contacts, said top wall of the shell provided with slots, and the screws having reduced neck portions in said slots whereby the screws are held against longitudinal movement in the upper member and operation of the screws in the other direction will shift the lower member away from the upper member and permit insertion of the conductor wires to the clamping position between them.

5. In an electrical device of the character described, a body of insulating material comprising upper and lower members, said lower member provided with longitudinal chambers including curved slots opening through its lower side and supporting shoulders on its upper side, stationary contact blades mounted in said chambers including laterally extending upper end portions supported on said shoulders and lower transversely curved blade portions in said slots and projecting from the under side of said lower member, said blades including an intermediate narrower portion and wider free end portions providing upwardly facing locking shoulders spaced below the under side of the lower member, the upper member provided with downwardly extending bosses on its lower side provided with downwardly facing radially extending recesses closed on their opposite sides and outer ends and open at their inner ends, said recesses being located 8 over the upper end portions of the contacts, said uppe member provided with passage means extending from its top side whereby the bared ends of conductor wires may be inserted in said recesses through the open sides thereof over said end portions, the outer closed ends of said recesses forming limit stops for said wires, and screws connecting said upper and lower members whereby said members may be drawn together to clamp the conductor wires to the contacts.

6. In an electrical device of the character described, a body of insulating material comprising upper and lower members, said lower member provided with longitudinal chambers including curved slots opening through its lower side and upwardly extending ribs on its upper side forming supporting shoulders at one side of said chambers, said shoulders provided with outwardly extending grooves, stationary blade contacts mounted in said chambers including transversely curved portions projecting from the lower side of said lower body member, said projecting portions including intermediate narrower portions and wider free end portions forming upwardly facing locking shoulders spaced from the lower side of the body member, the upper ends of the contacts being longitudinally slit providing lugs one of which is laterally curved and offset providing a plate portion seating on said supporting shoulder and having a rib on its under side seating in the groove in said shoulder, the upper body member provided with clamping surfaces on its under side over said supporting shoulders and passage means whereby the bared ends of conductor wires may be inserted to positions between said clamping surfaces and said plate portions, and screws connecting the body members whereby they may be drawn together to clamp the conductor wires to the contacts.

7. In an electrical device of the character described. a body of insulating material comprising upper and lower members, said lower member provided with longitudinal chambers including curved slots opening through its lower side with inwardly facing locking shoulders at one end and the inner side of the slots, said lower member also provided with a central boss at its upper side provided with recesses at the inner sides of said chambers. stationary contacts mounted in said chambers having laterally extending upper end portions seated in said recesses, the upper body member provided with clamping surfaces on its lower side over said upper end portions of the contacts and passage means extending from its top side whereby the bared ends of conductor wires may be inserted between said surfaces and these end portions, and screws connecting the body members whereby they may be drawn together to clamp the wires to the contacts.

8. In an electrical device of the character described, a body of insulating material comprising upper and lower members, said lower member provided with longitudinal chambers including curved slots opening through its lower side with inwardly facing locking shoulders at one end and the inner side of the slots, said lower member also provided with a central boss at its upper side provided with recesses at the inner sides of said chambers and supporting shoulders on the opposite sides of the chambers from the recesses, stationary contacts mounted in said chambers including laterally extending upper end portions each seated at one end in the adjacent recess and at the other end on the associated shoulder, the upper body member provided with clamping surfaces on its lower side over said upper end portions of the contacts and passage means extending from its upper side whereby the bared ends of conductor wires may be inserted between said surfaces and these end portions, and screws connecting the body members whereby they may be drawn together to clamp the wires to the contacts.

9. In an electrical device of the character described, a body of insulating material comprising upper and lower members, said lower member provided with longitudinal chambers opening through its top walls and supporting shoulders on its upper side on opposite sides of said chambers and downwardly extending recesses at the outer sides of the shoulders at the outer sides of said chambers, stationary contacts mounted in said chambers each comprising a transverse top plate member having a downwardly extending lug at its outer end and downwardly extending spring members secured at their upper ends to the under side of said plate, said spring members being located in the chambers with the top plate members supported on said shoulders and their downwardly extending lugs in said recesses, the upper body member provided with clamping surfaces on its under side over said top plate members and passage means extending from its upper side whereby the bared ends of conductor wires may be inserted between said surfaces and said plate members, and screws connecting the body members whereby they may be drawn together to clamp the wires to the contacts.

10. In an electrical device of the character described, a body of insulating material comprising upper and lower members, said lower member provided with longitudinal chambers opening through its top walls and supporting shoulders on its upper side on opposite sides of said chambers with a downwardly extending recess at the outer end of one of said shoulders. stationarv contacts mounted in said chambers each comprising a transverse top plate member and a downwardly extending member secured at its upper end to the under side of the plate member, said downwardly extending member being located in a chamber with the top plate supported on said shoulders, said top plate having a downwardly extending lug at one end in the adjacent recess, the upper body member provided with clamping surfaces on its under side over said top plate members and passage means extending from its upper side whereby the bared ends of conductor wires may be inserted between said surfaces and said plate members, and screws connecting the body members whereby they may be drawn together to clamp the wires to the contacts.

References Cited in the file of this patent UNITED STATES PATENTS 1,925,095 Halleburton Sept. 5, 1933 1,938,303 Tregoning Dec. 5, 1933 2,110,508 Klopfer Mar. 8, 1938 2,112,752 Abbott Mar. 29, 1938 2,430,593 Windsor Dec. 5, 1947 2,480,787 Stephan Aug. 30, 1949 2,648,051 Sprigg Aug. 4, 1953 

